Textile yarn and fabric



. duced with the aid of highly twisted cellulose Patented Nov. 19, 1935PATENT, OFFICE TEXTILE YARN AND FABRIC Henry Dreyfus, London, andWilliam Alexander Dickie andjiobert Wighton Moncrieff, Spondon, nearDerby, England, assilnors to Celanese Corporation of America, acorporation of Delaware No Drawing. Application May 11, 1932, Serial No.610,702. In Great Britain May 15, 1931 12 Claims.

This invention relates to the manufacture of textile fabrics and textileyarns suitable for incorporating therein, and is more particularlyconcerned with the production of fabrics exhibiting crepe effects.

Textile materials exhibiting crepe effects have longbeen obtained byemploying in their construction highly twisted yarns of natural silk inthe gummed state. Upon scouring such a fabric in an aqueous bath thewell-known crepe effects appear and the fabrics so obtained have longbeen highly prized on account of their great beauty and-pleasing handle.The production of crepe fabrics by utilizing highly twisted yarnsconsisting of or containing filaments of artificial silk has, however,been accompanied by considerable difllculties, more particularly in thecase of utilizing highly twisted yarns made of filaments of celluloseacetate.

In British Patent No. 348,589, there is, however, described a processwhereby there may be proacetate yarns, fabrics exhibiting crepe effectscomparable in character with those obtainable on According to thatspecification, the highly twistedcrpe threads are impregnated with asuitable material and after incorporation into fabrics, the fabrics aresubjected to a treatment adapted to swell the impregnating materials,which preferably have been so applied as to surround effectively thefilaments of the crepe threads. The swelling treatment is essentiallysuch "as will not render the impregnating material excessively soft oryielding. It appears that the swelling of the impregnating materialwithin the highly twisted crepe threads forces apart the filamentsthereof and so causes, on account of the high twist, a, diminution inthe length of the crepe threads. In this specification it will be noted,the means specified for effecting the swelling of the impregnatingmaterial and hence the shrinkage of the crpe threads, are

' physical in character.

soluble sulphate, for example potash alum, and thereafter treated with asolution of lead acetate in order to form lead sulphate within thehighly twisted crepe threads and scoured. The shrinkage consequent uponthe formation of the lead 5 sulphate may be due to the forcing apart ofthe filaments and the contraction brought about by the high twist, ormay be due to a strain set up by the increase in volume, or again may bedue to a strain set up by the surface contraction brought about by theformation of the solid material. Whatever the mechanism of the process,however, the yarns are constrained to shrink in length to a veryconsiderable degree and to give rise to, crepe effects of an excellencehitherto unattained or attained only with great difiiculty in the caseof fabrics containing highly twisted crepe threads of cellulose acetatefilaments. We have further found that the formation of other solid orsemi-solid materials within the crepe threads may be utilized in ananalogous manner for the production of crepe effects.

The formation of the solid or semi-solid materials may be effected inthe woven fabrics as outlined above or may be effected at other stagesof the manufacture of the fabrics. The compounds may for instance beproduced within the crepe threads prior to weaving and in fact at anyconvenient stage in their production, for example prior to theapplication of the high degree of twist requisite therein.

It has been found, however, that most satisfactory results are obtainedwhen the solid or semi-solid compound is formed within the crepe threadsin the finished fabrics. Moreover, it has been found that it isparticularly advantageous to incorporate a suitable reagent in the crepethreads prior to weaving and especially prior to the application of asubstantial proportion of the twist and then to convert the said reagentinto a suitable solid or semi-solid compound after the threads have beenincorporated into fabrics. Thus in the case wherein lead sulphate isproduced. within the crepe threads, cellulose acetate yarn of low twist,for example 5 turns per inch, may be impregnated with the potash alumin. the form of an aqueous solution and the impregnated yarn thereaftertwisted in one or more stages to the requisite high degree, for example50 to 60 turns per inch. The impregnated and 50 twisted yarn may then bewoven into a warp and the resulting fabric subjected to the action of anaqueous solution of lead acetate or other soluble lead salt, andthereafter scoured. By operating in this manner the formation of thelead sulphate 66 or other solid or semi-solid material is effected wellwithin the crepe threads and around the individual filamentsconstituting the latter. Shrinkage of the crepe threads to the maximumpossible degree is thereby assured.

The application of a reagent subsequently to be converted into a solidor semi-solid material may be effected in various ways. Thus, forexample the yarn to be utilized as crepe threads may be impregnated,either before or after crepe twisting, with a solution of the requisitereagent, while in the form of hanks or while wound on perforated bobbinsor other form of yarn container, and the impregnation may be assisted bythe employment of vacuum in the well-known manner. Most conveniently,however, the solution of the reagent may be applied to the yarn whilewinding from one package to another. The impregnated yarn may then bedried.

The application to the crepe threads of, part or the whole of therequisite high degree of twist may be effected simultaneously withsuch-an impregnating operation, the yarn being dried, if desired, bymeans of warm air or otherwise prior to the rewinding. Particularly goodresults are obtained, however, if at least a part of the crepe twist isapplied in an operation following the application of the reagent.Further, it is preferred to apply the high degree of twist in two ormore stages rather than in a single operation. Thus, yarn of low twistmay be passed through a solution of the reagent, dried if desired, andthen twisted to 15 to 30 turns per pinch and thereafter to the highdegree necessary in the final threads, for example 45 to 70 turns perinch or more, e. g. turns per inch, in a second operation.Alternatively, the reagent may be applied between the two twistingoperations and, if desired, simultaneously with one of them. In practicevery good results may -be obtained by twisting yarn of about 5 turns perinch up to about 25 turns per inch on a machine of the type in whichtwist is applied as the'yam is drawn off its package, the drawn off andtwisted yarn being passed through the aqueous or other solution of thereagent on the way to the rewinding device. The yarn so produced isthereafter twisted to 50 to 60 turns per inch or more in a separateoperation. I

Solid or semi-solid materials of widely varying character may beproduced by chemical means within the crepe threads and around thefilaments thereof in-the production of fabrics exhibiting crepe effectsin accordance with the present invention. As, however, it"is usuallymost convenient to utilize aqueousreagents in the production of saidmaterials, materials which are not soluble or are only diflicultlysoluble in water are to .bepreferred. As examples of such com-- als,where these are sufficiently difficultly soluble in water.

The difficultly soluble salts may comprise eithe organic or inorganicacid radicles. For example,

there may beutllized the sulphates, carbonates or phosphates of thealkaline earth metals or of lead, or the carbonates or phosphates ofother of the foregoing metals. In practice, however,

the diflicultly solubleiorganic acid salts of the foregoing metals havebeen found especially convenient. As examples of such organic acids,mention may be made of dior poly-basic carboxylic acids or diorpoly-basic hydroxy carboxylic acids, for example, oxalic acid, tartaric.acid, citric acid, mucic acid or saccharic acid. 5 Again, there may bementioned the higher fatty acids, for example oleic, stearic, palmitic,ricinoleic or lauric acid. All of these acids are capable of yieldingdifficultly soluble salts with one or other of the foregoing metals.Other difficultly l0 soluble compounds may be utilized, however, forexample metal compounds of casein or other albuminous materials.

The reactions involved in the production of the insoluble or diflicultlysoluble materials may 15 be of any desired character, for exampledifiicultly soluble metal salts may be produced by interaction between awater-soluble salt of the metal and a water-soluble alkali metal salt ofthe appropriate acid, e. g. sodium citrate, sodium 0 tartrate, orRochelle salt. Again, an appropriate acid may be caused to react with awater-soluble hydroxide of a metal, for example calcium or bariumhydroxide.

As one of the reagents is in general preferably 25 applied to the crepethreads during their manu facture and prior to the application of atleast part of the twist, the reagent so applied will in general, thoughnot necessarily, be in substantially solid form in the material at thetime of applying a further reagent or reagents and the reactionrequisite for the production of the solid or semi-solid salt or othercompound will therefore generally be between a solid reagent and anotherreagent, the latter usually in the form of an aqueous or other solution.If desired, however, a second or subsequent reagent may be applied inthe form of a gas; for example, ammonia may be caused to react with analuminium salt so as to produce aluminium hydroxide within the crepethreads.

The compounds formed within the materials and the reagents used toeffect the said formation may with advantage be such that the bulk ofthe material formed is relatively large in comparison 40 with the bulkof the reagent first applied to or incorporated within the crepethreads.

of an insoluble or difllculty soluble metal salt, which when preparedwith the aid of an aqueous solution, prior to or during the applicationof the high crepe twist and are then treated with bariumhydroxideuafter, weaving into fabrics, a large increasein the bulk oftheyarn takes place and a corresponding shrinkage in length on account ofthe high twist. Other' compounds may likewise be produced in hydrated,solid or semisolid form, for-example other metal salts or aluminium orother metal hydroxide.

As previously indicated it is usually most convenient from the point ofview of ease of application to produce within the crepe threadsmaterials which are insoluble or diiilcultly soluble in water. Theinvention is not however restricted to the use of such materials, asmaterials having appreciable solubility in water may be utilized,

- providing they are produced with reagents in an appropriate form. Forexample, if aqueous reagents are used there,may be added thereto alkalimetal salts, for example sodium chloride or potassium chloride or othersubstances capable of diminishing the solubility in water of thematerial it is desired to produce within the crepe threads. In the case,for instance, of producing barium citrate or other difiicultly solublesalt from an acid and a base, material impregnated with an appropriateacid may be treated with a solution of the base, for example bariumhydroxide, containing ethyl alcohol or containing sodium chloride insubstantial proportion, e. g. up to saturation, in order to assist theseparation of the barium citrate or other material within the crepethreads and prevent its solution by the aqueous reagent employed. Suchadditions of alcohol, salts, and the like to reagents may also serve toprevent solution and removal from the crpe threads of citric acid orother reagenttherein prior to its conversion into the desired solidcompound. This method of assisting the formation of the desiredcompounds within the materials constitutes an important and valuablefeature of the present invention, more particularly so in view of thefact that many of the compounds, for example, a hydrated barium citrateor other hydrated salts'of organic acids which may be producediii-relatively large bulk from relatively small quantities of reagent inthe crepe threads, are appreciably soluble in water itself but are lesssoluble-in aqueous alcohol or concentrated solutions of sodium chlorideor other salts.

In general the reactions utilized for the production of the solid orsemi-solid materials within the crepe threads may be advantageouslyeffected under such conditions as to separate the material in maximumquantity and in the most advantageous physical form from the point ofview of securing good shrinkage of the crepe threads. It is oftenbeneficial for example to effect the reactions at elevated temperaturesor to leave the materials in contact with the reagents for prolongedperiods, for example 12 to 24 hours, or to incorporate wetting agents inthe reagents. When forming calcium citrate from citric acid or sodiumcitrate andcalciunr chloride the fabric containing highly twisted yarnsprepared with citric acid. or sodium citrate maybe left in contact withcalcium chloride solution, preferably highly concentrated for severalhours with or without heating. Again, when producing barium citrate, forinstance,.in the above described manner, the barium hydroxide solution,whether containing or not alcohol or salts or. other additions, may withadvantage be applied at 60-80 C. or even at temperatures up to theboiling point.

It has further been found that-instead of or in addition to applyingheat during the formation of the insoluble or diflicultly solublecompounds, the materials may with great advantage subsequentlybe'subjected to a hot aqueous treatment, for example in an aqueousscouring bath, e. g. a both containing a soap or sulphonated soap, forinstance Turkey red oil, or a wetting agent. In the case of materialscontaining cellulose acetate crepe threads the hot aqueous treatment ispreferably carried out at temperatures above C., e. g. at 80-85 C. oreven at temperatures up to scribed in British Patent No. 352,451,

' alkaline earth hydroxide.

c. Hot aqueous baths may contain neutral salts or other substancesadaptedto minimize reduction of lustre.

The proportions of reagent incorporated in the crepe threads may varywithin wide limits and according to the nature of the reactions to beutilized and the effects it is desired to produce. The proportionincorporated may be regulated for instance by varying either thequantity or concentration or both quantity and concentration of thesolution in which the said reagent is applied. In the case of producingbarium citrate for instance, citric acid may be incorporated in theproportion of 1 to 5 per cent. or more of the weight of the threads;applied in the form of aqueous solutions of 10, 20 or 30 per cent.concentration or even of concentrations up to that of saturatedsolutions.

After the dimcultly soluble metal salts or other solid materialsproduced within the crepe threads have served their purpose in theproduction of the desired crepe effects, they may be removed from thefabrics if desired or requisite. In general, it will be found convenientto select compounds which admit of ready removal from textile materials.Such removal may be effected in many cases by simple mechanical means,for example by thorough washing and agitation with water or otherliquids, or by chemical means ascording to the precise nature of thematerial in question. Where-a hot aqueous scour or like treatment isapplied in the manner previously indicated, such treatment maysimultaneously serve to effect the removal of the diflicultly solublecompounds.

The crepe threads employed in accordance with the present invention may,if desired, be sized at any suitable stage of their manufacture. In thisconnection particular mention may be made of sizing materials which maybe caused to swell without becoming soft or yielding by suitabletreatment, particularly by the subsequent treatment of the fabrics inordertoproduce,

by chemical means, suitable compounds therein or by a scouring treatmentwhere such is employed. The sizing materials may be selected withadvantage according to the principles laid down in British Patent No.348,589. Again, the

crepe threads or the filaments contained therein may be sized with orprovided with a coating of a cellulose or a cellulose derivative asdescribed in British Patent No. 357,169, or with a coating of apolymerized vinyl compound or other polymerized or condensed organiccompound as .de-

'Any sizes or coatings m'ay be applied intermittently to the threads asdescribedin U. S. Patent No. 1,966,440 and British Patent No. 365,041.

Sizing materials, where. employed, are prefer ably applied to or formedon the crepe threads prior to the application of a substantial degree oftwist and convenently may be applied simultaneously with a reagentadapted subsequently to be converted by chemical means into a mate--rial of greater bulk in accordance with the foregoing processes. Acasein size saturated with citric acid or other suitable organic acidmay, for example, be employed, and the fabrics subsequently treatedwith'a solution of barium or other In this. manner there may besimultaneously effected a swelling of the casein size and a formation ofbarium or other alkaline earth citrate or other compound, whereby asubstantial shrinkage of the crpe threads may be caused to take place.

Again, the treatment applied to produce by chemical means within thecrepe threads a suitable solid or semi-solid material, may be one whichis also adapted to cause a swelling of the material of the crepe threadfilaments without causing it to become excessively soft or yielding ormay be applied in conjunction with such a swelling treatment. Forexamples of such swelling treatments reference may be made to U. S.Patent No. 1,995,296 and British Patents Nos. 352,000 and 357,084. Forinstance, where an acid is employed for the production of .the requisitematerial by chemical means within the crepe threads, the acid may be onecapable of swelling cellulose acetate material in the presence of wateror may be applied in admixture with such a substance, e. g. alcohol. Theacid may, for instance, be applied to the crepe threads prior totwisting in the form of an alcoholic solution. Crepe threads may thus beproduced which, upon treatment with an aqueous solution containing asuitable base, for example barium hydroxide, have formed therein aninsoluble barium salt of the acid utilized, while at the same time aswelling of the material of the filaments takes place. Again, celluloseacetate yarn may, either before or after crepe twisting, be dehydratedby means of a concentrated calcium chloride solution, as described inBritish Patent No. 357,084, woven into fabrics and the latter treatedwith a reagent capable of forming an insoluble calcium salt with calicumchloride. Such a reagent may, for instance, be a soluble sulphate,carbonate or suitable salt of an organic acid. Alternatively, one of thelatter reagents may be incorporated in the crepe threads, the latterwoven into fabrics and the said fabrics subjected to the action of aconcentrated solution of calcium chloride and finally washed or scoured.In these ways also' simultaneous swell'ng and production of solidmaterial, e. g. calcium sulphate or carbonate, within the crepe threadsmay be efiected. If desired, however, a swelling treatment may beapplied in an operation independent of the process of producing thesolid or semi-solid material within the crepe threads.

As stated previously, the invention is of particular value in connectionwith the production of crepe fabrics with the aid of highly twistedyarns consisting of cellulose acetate filaments. Crepe threadscomprising filaments of other organic derivatives of cellulose may beemployed in an analogous manner. As examples of such cellulosederivatives may be mentioned cellulose formate, propionate or butyrateor other cellulose esters of organic acids, or methyl, ethyl or benzylcellulose or other cellulose ethers. If desired, crepe threadsconsisting of. or comprising filaments of other materials may beemployed, for example filaments of silk, cotton, or of artificial silkof the regenerated cellulose type. The crepe threads may also becomposed of filaments of two or more different kinds whether in respectof material or denier or both. Thus there may be used threads containingboth filaments or cellulose esters or ethers and filaments of naturalsilk or regenerated cellulose artificial silk, or threads containingcellulose ester or ether filaments of two or more difierent deniers.Further, the crepe yarns may consist, wholly or in part, of staplefibre" i. e. relatively short lengths of filament.

The degree of twist imparted to the crepe threads made or used accordingto the present invention, may be similar to that commonly employed inthe case of crepe threads of natural silk in the gum. For example, aspreviously indicated, a twist of from 45-70 turns per inch may beemployed. In general a twist of about 60-65 turns per inch has beenfound to give highly satisfactory results, but higher twists, forexample 5 75-85 or more turns per inch, may be employed with advantagein some. cases, particularly when the filaments are of very low denier(see British Patent No. 357,577). Any other suitable degree of twistmay, however, be employed according to the nature and denier of thefilaments constituting the crepe threads and according to the effects itis desired to produce. Moreover, the twist may be irregular incharacter, varying frompoint to point along the crepe thread, asdescribed in British Patent No. 358,585. Further, the requisite highdegree of twist may be applied in two or more stages with or withoutintermediate sizing, in the manner described in British Patents Nos.332,903 and 375,355.

The highly twisted crepe threads may be incorporated in the fabrics inany suitable manner, for example the weft alone may be wholly orpartially composed of such threads or the warp may also contain them. Inthe former case the finished fabrics exhibit chiefly shrinkage in thedirection of the weft. It is found particularly convenient however, ingeneraLto employ threads of relatively low twist in the warp and toemploy in the weft both crepe threads having a left-hand twist and crepethreads having a right-hand twist. Such threads may be disposed in thefabrics in any convenient manner, for example pairs of threads ofleft-hand twist may alternate with pairs of threads of right-hand twist.A further method of constructing the fabrics is to weave composite crepethreads consisting of a yarn of high twist doubled with a yarn of lowtwist, or consisting of two yarns of high but opposite direction oftwist, the yarns being prepared and the fabrics subsequently treated inaccordance with the processes of the invention. In this manner crepefabrics may be readily produced without the necessity for the employmentof a loom capable of weaving two different types of yarn such as isnecessary when alternate picks of yarn of left-handed twist and yarn ofright-handed twist are to be woven. In this'connection reference is madeto U. S. applications S. Nos. 444,619, filed 15th April, 1930 and589,304, filed 27th 1 January, 1932.

Where the fabrics comprise yarns of low twist, the latter may be eitherof the same material or of a different material from that of the highlytwisted crepe threads. For example, where the crepe threads are composedof cellulose acetate filaments, the said yarns of low twist may becomposed of cotton or of a regenerated cellulose type of artificialsilk.

In the case of fabrics containing low twist yarns as well as the highlytwisted crepe threads, such yarns, particularly when forming the warp ofthe material, will usually be sized. In this event it has been foundbeneficial to employ sizes which are easily removed or at least easilysoft- 5 ened by the treatments subsequently to be applied to the fabricsin accordance with the invention. Indeed, if desired, the saidtreatments may be modified, for example in respect of temperature orother conditions, or a special treatment may be applied, for thepurposeof softening or removing the size on the yarn of low twist.

Preferably the size on the said low twist yarns should be more easilysoftened or removed than any size which may have been applied to thehighly twisted crepe threads in the fabrics. Again, when utilizing yarnsof low twist in con junction with the crepe threads of high twist, thesaid low twist yarns may be of such character or be so treated as to beless readily wetted than the crepe threads. For instance they may beoiled with an animal, vegetable, or mineral oil prior to incorporationinto the fabrics.

The invention is illustrated but not limited by the following examples:-

Example 1 Cellulose acetate yarn of 100 denier 26 filaments, twisted toone turn per inch, is twisted to 26 turns per inch and then passed overa roller revolving in a bath of citric acid solution of 10 per cent.strength. The yarn is subsequently twisted up to 67 turns per inch. Yarnof lefthand twist as well as yarn of right-hand twist is prepared. Thetwisted and treated yarn is then woven into a warp consisting ofcellulose acetate threads of denier, twisted one turn per inch, twopicks of left-hand twisted yarn alternating with two picks of righthandtwisted yarn in the weft, the total number of picks being per inch.

The resulting fabric is then immersed for several hours in a two percent. aqueous solution of barium acetate, preferably containing a smallproportion of alcohol. The fabric is thereafter washed, dyed andfinished.

Example 2 Cellulose acetate yarn of 75 denier is twisted to 26 turns perinch, passed through a concentrated solution of lead acetate andthereafter twisted up to '70 turns per inch. The resulting treated andtwisted yarn is thereafter woven into a warp containing 80 ends per inchof cellulose acetateyarn of 75 denier and 22 turns per inch twist. 80picks per inch of weft are employed with a 5 shaft satin weave. Thewoven fabric is then immersed for some time in a 10 per cent. aqueoussolution of potash alum, and is subsequently scoured and finished.

Example 3 Cellulose acetate yarn of denier is twisted to 26 turns perinch and treated with a 30 per cent. solution of sodium citrate. Theyarn is then further twisted up to 67 turns per inch righthand. Afurther quan 'ty of yarn is prepared in the same manner but withleft-hand twist. The prepared yarn is thereafter woven into a celluloseacetate warp of low twist, two picks of left-hand twist yarn alternatingwith two picks of righthand twist yarn. The fabric is then immersed forseveral hours in a solution containing 4 per cent. of barium hydroxideand saturated with common salt. The resulting fabric is finally scouredand finished. 1

Example 4 Cellulose acetate staple fibre yarn of 12s cotton counts with20 turns per inch twist is passed through a 30 per cent. solution ofcitric acid. It is then twisted up to 62 turns per inch right-hand,

a similar quantity of yarn being prepared in the.

Patent 18:-

.agent adapted to react with the first reagent to 1. Process for theproduction of a fabric exhibiting crepe effects whichcomprises'incorporating in a fabric -a highly twisted thread produced byapplying part of the high twist 'to a thread, impregnating the partlytwisted thread 5 with a suitable reagent and then completing the hightwist, and thereafter subjecting the fabric to theaction of a reagentadapted to react with the first reagent to form a solid material in thehighly twisted threads. 10

2. Process for the production of a fabric exhibiting crepe effects whichcomprises incorporating in a fabric a highly twisted thread produced byapplying part of the high twist to a thread of filaments of an organicderivative of 15 cellulose, impregnating the partly twisted thread witha suitable reagent andthen completing the high twist, and thereaftersubjecting the fabric to the action of' a reagent adapted to react withthe first reagent to form a solid material in the 20 highly twistedthreads.

3. Process for the production of a fabric exhibiting crepe effects whichcomprises incorporating in a fabric a highly twisted thread produced byapplying part of the high twist to a 25 thread of cellulose acetate,impregnating the partly twisted thread with a suitable reagent and thencompleting the high twist, and thereafter subjecting the fabric to theaction of a reagent adapted to react with the first reagent to form a 30solid material in the highly twisted threads.

4. Process for the production of a fabric exduced by twisting celluloseacetate thread to at 35 least 15 turns per inch, impregnating the partlytwisted thread with a suitable aqueous reagent and then completing thehigh twist, and thereafter subjecting the fabric to the action of areform a solid material in the highly twisted threads.

5. Process according to claim 4 wherein the total twist is 60-85 turnsper inch.

6. Process for the production of a fabric exhibiting crepe effects whichcomprises incorporating 45 in a fabric a highly twisted thread producedby twisting cellulose acetate thread to at least 15 turns per inch,impregnating the partly twisted thread with an aqueous solution of asalt and then completing the high twist, and thereafter 5o subjectingthe fabric to the action of a reagent adapted to react with the salt toform a solid material in the highly twisted threads.

7. Process for the production of a fabric exhibiting crepe effects whichcomprises incorpo- 5 rating in a fabric a highly twisted thread producedby twisting cellulose acetate thread to at least 15 turns per inch,impregnating the partly twisted thread with an aqueous solution of analkali metal salt and then completing the high twist, and thereaftersubjecting the fabric to the action of a reagent adapted to react withthe salt to form a solid insoluble salt in the highly twisted threads.65

8. Process for the production of a fabric exhibiting crepe effects whichcomprises incorporating in' a fabric a highly twisted thread produced bytwisting cellulose acetate thread to at least 15 turns per inch,impregnating the partly 7 twisted thread with an aqueous solution of analkali metal salt of an acid containing at least two carbonyl groups andthen completing the high twist, and thereafter subjecting the fabric tothe action of areagent adapted to react with It boxylic acid in thehighly twisted threads.

9. Process for the production of a fabric exhibiting crepe efiects whichcomprises incorporating ina fabric a highly twisted thread produced bytwisting cellulose acetate thread to at least 15 turns per inch,impregnating the partly twisted thread with an aqueous solution of analkali metal salt of citric acid and then completing the high twist, andthereafter subjecting the fabric to the action of an aqueous solution ofan alkaline earth salt.

10. Process for the production of a fabric exhibiting crpe effects whichcomprises incorporating in a fabric a highly twisted thread produced bytwisting cellulose acetate thread to at least 15 turns per inch,impregnating the partly twisted thread with aqueous citric acid and thencompleting'the high twist, and thereafter subjecting the fabric totheaction of an aqueous solution of an alkaline earth hydroxide.

11. Process for the production of a fabric exhibiting crepe effectswhich comprises incorporatthe salt to form a solid insoluble salt of thecaring in a. fabric a highly twisted thread produced by twistingcellulose acetate thread to atleast 15 turns per inch, impregnating thepartly twisted thread with aqueous citric, acid and then completing thehigh twist, and thereafter subjecting 5 12. Process for the productionof a fabric exhibiting crepe effects which comprises incorporating in afabric a highlytwisted thread produced 10 by twisting cellulose acetatethread to at least 15 turns per inch, impregnating the partly twistedthread with a suitable aqueous reagent and then completing the hightwist, and thereafter subjecting the fabric to the action of an aqueoussolu- 15 tion of a reagent adapted to react with the first reagent toform a solid material in the highly twisted threads, said aqueousreagent containing a substance minimizing solution of the first reagentfrom the material. g0

HENRY DREYFUS.

WILLIAM ALEXANDER DICKIE. ROBERT WIGHTON MONCRIEFF.

CERTIFICATE OF CORRECTION.

Patent No. 2,021,717. November 19, 1935.

HENRY DREYFUS, ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows; Page 2,first column, line 33, for

"pinch" read inch; page 4, second column, line 19, for "Patents Nos."read Patent No.; line 20, for "332,903 and 375, 355" read 357,576; line49, beginning with"U. S." strike out ali to and including "i932" in line51, and insert instead British Patents N0s.332,903

and 375,355; and that the said Letters Patent should be read withthcse-c0rrections therein that the same may conform to the record of thecase in the Patent Office.

Signed and sealed this 14th day of January, A. D. 1936.

Leslie Frazer (Seal) Acting Commissioner of Patents.

